Display device

ABSTRACT

The present invention provides a display device where the printed portion on the front window can be prevented from being shaved and defects can be prevented from being produced, and this display device has a display panel and a front window (FW) provided on the front side of the display panel and is characterized by having; a plate member (TP) pasted to the rear surface of the front window which is smaller than the front window; an adhesive film ( 30 ) for pasting the front window and the plate member together that is smaller than the plate member; and a printed portion ( 20 ) printed on the rear surface of the front window and formed around the display region of the display panel, and in the region ( 23 ) where the front window makes contact with the edge of the plate member, the printed portion is thicker than the other regions.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority over Japanese application JP2010-078937, filed on Mar. 30, 2010, the contents of which are hereby incorporated into this application by reference.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a display device, and in particular to a display device having a front window.

(2) Description of the Related Art

Various types of display devices, such as liquid crystal modules (liquid crystal display devices) and organic electroluminescent display devices, are used for various portable information apparatuses, such as portable phones, portable information terminals (PDA's), digital cameras and multimedia players.

As shown in JP2010-237447A, in recent years, general display devices have had a hybrid structure where a transparent protective cover has been pasted as a front window in order to protect the display panel. In addition, multifunctional display devices having a touch panel (TP) have also been provided, and thus a structure where a touch panel and a front window are pasted on the front surface of the display panel on top of each other has been proposed.

In the touch panel shown in FIG. 1, a flexible printed circuit 11 for wiring the system is connected to a capacitor-type touch panel glass (touch panel screen portion) 1, and furthermore an electronic part 12 for controlling the operation of the touch panel is provided if necessary and an interface terminal portion 13 is formed on the other end of the flexible printed circuit. FIG. 2 shows the exterior of the front window.

Meanwhile, the front window (FW) has a printed portion 20 on the rear surface except in the image display region of the display panel. In particular, the printed portion is colored black or a similar color in liquid crystal display devices in order to prevent light from the backlight from leaking through a place other than the image display region.

FIG. 3 is a plan diagram showing the touch panel (TP) in FIG. 1 in a state where it is pasted to a front window (FW). FIG. 4 is a cross sectional diagram along single-dotted chain line X-X′ in FIG. 3. 30 is an adhesive film for pasting the front window and the touch panel together.

Members, such as a touch panel (TP), pasted to the front window (FW) are usually smaller than the front window, and the adhesive film 30 is further smaller and smaller than the touch panel. Therefore, as shown in FIG. 5, when pressure is applied to the edge of the front window, the front window (FW) bends and makes contact with the edge of the touch panel (TP) at point A, and thus may shave part of the printed portion 20, which ends up making the printed portion defective.

Though it is possible to provide a buffering material between the printed portion 20 and the touch panel (TP), the gap between the two is as narrow as 0.1 mm or less, and therefore it is difficult to provide a buffering material.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the above described problem and to provide a display device where the printed portion on the front window can be prevented from being shaved, and thus defects can be prevented from being produced.

As a result of diligent research, the present inventors have proposed a method for preventing the edge of the touch panel or the like from completely shaving the printed portion through contact by making the printed portion 21 on the front window thicker, as shown in FIG. 6. However, when the printed portion is thicker than 10 μm, bubbles (defects in the adhesive film) are easily created in the vicinity of the portions where the printed portion 21 and the adhesive film 30 overlap (B and C), and thus it has been found that a new defect may arise.

In addition, as shown in FIG. 7, it has been proposed to form a thin printed region 22 having a thickness of 10 μm or less inside the thick printed portion 21 and provide an adhesive film 30 so that it overlaps the printed region 22. However, the distance S between the adhesive film 30 and the edge of the touch panel (TP) is great, and therefore it has been found that a new problem may arise such that the touch panel (TP) easily peels from the front window.

The present inventors have figured out means and ways to solve the above described problem, and thus invented a display device having the following features.

-   -   (1) A display device having a display panel and a front window         provided on the front side of the display panel is characterized         by having; a plate member which is pasted to the rear surface of         the front window and is smaller than the front window; an         adhesive film for pasting the front window and the plate member         together that is smaller than the plate member; and a printed         portion printed on the rear surface of the front window and         formed around the display region of the display panel, and in         the region through which the front window and the edge of the         plate member make contact with each other, the printed portion         is thicker than the other regions.     -   (2) The display device according to (1) is characterized in that         the region where the printed portion is thicker corresponds to a         corner of the plate member.     -   (3) The display device according to (1) or (2) is characterized         in that the region where the printed portion is thicker has a         width of 0.5 mm or more with the point at which the edge of the         plate member is located at the center.     -   (4) The display device according to any of (1) to (3) is         characterized in that printing is carried out two or more times         in the region where the printed portion is thick.     -   (5) The display device according to any of (1) to (4) is         characterized in that the plate member is either a touch panel         screen portion or the display panel.

According to the present invention, in the region where the front window makes contact with the edge of the plate member, the printed portion on the front window is thicker than the other regions, and therefore the printed portion is not completely shaved as a result of contact of the edge of the plate member, such as the touch panel, and the printed member, and thus defects can be prevented from being produced.

In addition, the printed portion where the adhesive film is formed is as thin as the conventional printed portion, and therefore no bubbles are created between the front window and the adhesive film or between the plate member and the adhesive film. Furthermore, the distance between the adhesive film and the edge of the plate member is short, and thus it is possible to prevent the plate member from peeling from the front window.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan diagram showing a touch panel;

FIG. 2 is a plan diagram showing a front window;

FIG. 3 is a plan diagram showing the front window and the touch panel when they are pasted together;

FIG. 4 is a cross sectional diagram along the single-dotted chain line X-X′ in FIG. 3;

FIG. 5 is a diagram illustrating the front window in a bent state;

FIG. 6 is a diagram illustrating a case where the printed portion is thick;

FIG. 7 is a diagram illustrating a case where a thin printed portion is provided inside a thick printed portion;

FIG. 8 is a plan diagram showing the display device according to the present invention; and

FIG. 9 is a cross sectional diagram along the single-dotted chain line X-X′ in FIG. 8.

DESCRIPTION OF THE EMBODIMENTS

The appearance of the touch panel having a front window according to the present invention is the same as in FIGS. 1 and 2, and therefore the descriptions thereof are not repeated. The features of the present invention are described in detail below. FIG. 8 is a plan diagram showing the display device according to the present invention, and FIG. 9 is a cross sectional diagram along the single-dotted chain line X-X′ in FIG. 8.

The display device having a display panel (not shown) and a front window (FW) provided on the front side of the display panel according to the present invention is characterized by having a plate member (TP) that is pasted to the rear surface of the front window and smaller than the front window, an adhesive film (30) for pasting the front window and the plate member together that is smaller than the plate member, and a printed portion (20) printed on the rear surface of the front window and formed around the display region of the display panel, wherein the regions where the front window and the edge of the plate member make contact with each other (regions where 23 is formed), the printed portion is thicker than the other regions.

A resin-based material, such as an acryl-based material, is appropriate for use as the front window. In addition, it is possible to use a reinforced glass to which a scattering preventing film is pasted.

An example of the plate member pasted to the front window is a touch panel as that shown in JP2010-237447A. In this case, the portion where the touch panel is pasted to the front window (FW) by means of an adhesive film becomes a touch panel screen portion. It is also possible to paste the display panel instead of the touch panel to the front window. In the case where the display panel is a liquid crystal display panel or an organic electroluminescent display panel, the polarizing plate provided on this display panel is pasted to the front window by means of an adhesive film.

It is preferable for the regions where the printed portion is thick to be regions corresponding to the corners of the plate member (touch panel TP) as shown in FIG. 8. This is because the corners of the front window (FW) are easier to bend than the rest and the corners of the plate member easily shave the printed portions.

It is preferable for the regions (23) where the printed portion is thicker to have a width (d) of 0.5 mm or more with the point (E) at which an edge of the plate member is located at the center. In general, the allowance in the precision for assembly of the plate member, such as a touch panel (TP), and the front window is set to 0.2 mm or less. Therefore, even in the case where the plate member shifts relative to the front window in this range, the edges of the plate member are always located within the thick printed regions in the structure.

It is preferable for the thick printed portions to be formed by carrying out printing two or more times in the regions. As a result, it is possible to form the thick printed portions easily. Here, the thickness of the regions other than the thick printed portions is set to 10 μm or less so that no bubbles are created in the adhesive film.

As described above, the present invention makes it possible to provide a display device where the printed portions on the front window can be prevented from being shaved and defects can be prevented from being produced. 

1. A display device having a display panel and a front window provided on the front side of the display panel, characterized by comprising: a plate member which is pasted to the rear surface of the front window and is smaller than the front window; an adhesive film for pasting the front window and the plate member together that is smaller than the plate member; and a printed portion printed on the rear surface of the front window and formed around the display region of the display panel, and in the region through which the front window and the edge of the plate member make contact with each other, the printed portion is thicker than the other regions.
 2. The display device according to claim 1, characterized in that the region where the printed portion is thicker corresponds to a corner of the plate member.
 3. The display device according to claim 1, characterized in that the region where the printed portion is thicker has a width of 0.5 mm or more with the point at which the edge of the plate member is located at the center.
 4. The display device according to claim 1, characterized in that printing is carried out two or more times in the region where the printed portion is thick.
 5. The display device according to claim 1, characterized in that the plate member is either a touch panel screen portion or the display panel. 